EP2102026A1

EP2102026A1 - Fuel tank made of thermoplastic synthetic material with functional built-in structures for ventilation and deaeration, for the withdrawing of fuel or the like

Info

Publication number: EP2102026A1
Application number: EP07819883A
Authority: EP
Inventors: Matthias Borchert; Dirk Eulitz; Klaus Gebert; Timo Krämer; Harald Lorenz; Gerd Wolter
Original assignee: Kautex Textron GmbH and Co KG
Current assignee: Kautex Textron GmbH and Co KG
Priority date: 2006-12-15
Filing date: 2007-11-21
Publication date: 2009-09-23
Anticipated expiration: 2027-11-21
Also published as: ES2419233T3; DE102006059799A1; WO2008071299A1; EP2102026B1

Abstract

The invention relates to a fuel tank (1) made of thermoplastic synthetic material with functional built-in structures for ventilation and deaeration, for withdrawing fuel or the like. Said fuel tank is characterized in that at least one functional built-in structure (2, 9a, 9b) is adhesively bonded with the inner wall (3) of the tank such that the functional built-in structure (2, 9a, 9b) defines, with the tank wall, a volume separated from the filling volume of the tank in such a way that the inner wall (3) of the tank serves directly as a boundary wall of this volume.

Description

Fuel tank made of thermoplastic material with functional fittings for ventilation, for fuel extraction or the like

The invention relates to a fuel tank made of thermoplastic material with functional fittings for ventilation, for fuel extraction or the like.

The invention particularly relates to an extrusion blow molded fuel tank made of thermoplastic material. Such containers are usually made in one piece from one or more tubular preforms, which are applied by means of gas pressure to the wall of a multi-part mold or are widened in this. Depending on how the formation of the container is accomplished in the tool, built-in components are introduced into the container either after its completion by one or more mounting holes and fixed or the functional components are already introduced during the formation of the container in this. If the container is blow-molded from a tube, the diameter of the preform is usually dimensioned such that it can be extruded via a built-in holder with built-in components arranged thereon.

The welding of built-in parts with the inner wall of the container in the first heat during the formation of the container has proved to be unfavorable especially for larger components such as surge tanks or the like, since the cooling of the container wall after completion of the article in the areas in which on the inner wall the container welding surfaces are provided is obstructed. If, for example, in the fuel tank, a surge tank with its ground contact area is welded over a large area to the inner wall of the container, the cooling of the container wall upon cooling of the article is impeded over a large area. In particular, the internal cooling of the finished article by gas / air flushing is impaired. Due to the area-wise larger accumulation of material on the container inner wall, a shrinkage distortion of the material, which is visible on the outside of the container, may occur. In principle, however, for reasons of procedural simplification, it would be desirable to provide one-piece containers made of thermoplastic material, which are equipped with fixtures which were connected to the container wall during manufacture in the first heat.

The invention is therefore an object of the invention to provide a fuel tank made of thermoplastic material with functional installations for ventilation and exhaust, for fuel extraction or the like, in which the

Functional components are connected to the container wall and in which the functional components have been connected during the formation of the container in the first heat with this, the container should not have the aforementioned disadvantages.

The object is achieved by a fuel tank of thermoplastic material of the type mentioned, which is characterized in that at least one functional component is materially connected in such a manner with the inner wall of the container, that the functional component with the container wall defines a volume separated from the filling volume of the container, such that the inner wall of the container directly serves as a boundary wall of this volume.

The invention can be summarized to the effect that in the fuel tank such functional components are introduced, the first in

Cooperation with the inner wall of the container obtained full functionality, so that the inner wall of the container takes over a part of the functionality of the component in question and also acts as a boundary wall of the functional component. For example, profile sections can be provided as functional fixtures which are welded to the inner wall of the container in such a way that they form at least partially closed channels or volumes with the inner wall of the container. For example, the profile sections in cross section may be semicircular, U-shaped or V-shaped.

In a particularly preferred variant of the invention, at least one surge tank for a fuel pump is provided, which on its in

Installation position of the inner wall of the container facing side is open and the boundary wall is circumferentially cohesively connected to the inner wall of the container. In this way, a collection of material on the container inner wall is avoided, which arises because the bottom of the surge tank over its entire surface rests on the inner wall of the fuel tank. In the variant according to the invention, the fuel tank itself forms the bottom of the surge tank. In this way, a surge tank can be used advantageously, which is formed at least partially closed on its side facing away from the inner wall of the container side. Such a surge tank, for example, as one piece by

Injection molding manufactured plastic component may be formed. The ability to form the surge tank in one piece or in one piece, results in particular by the fact that the surge tank is closed during assembly or connection with the inner wall of the fuel tank through the wall of the fuel tank.

The fact that the side facing away from the inner wall of the container side of the surge tank should be formed closed, it is understood, of course, that the surge tank connections, nipples or breakthroughs may have to be introduced into this or be led out of this lines.

Appropriately, the boundary wall of the surge tank is provided on the side facing the installation position of the inner wall of the container with a peripheral mounting flange.

In order to achieve the best possible circumferential cohesive connection between the mounting flange on the one hand and the inner wall of the container on the other hand, the joining surface of the mounting flange can be profiled be. Alternatively, the joining surface of the mounting flange may be provided with melt projections and / or with melt approaches. These are thin material protrusions or material approaches, ribs or webs to understand that have a relatively low heat capacity and melt on contact of the relevant parts of the joint surface with the still hot inner wall of the container due to their low heat capacity and thus contribute to the formation of a reliable weld.

The boundary wall of the surge tank may be at least partially flexible and formed at least partially relative to the circumference of the surge tank. For example, the boundary wall of the surge tank having a circumferential film hinge or the like, so that the angle between the mounting flange and the container wall is variable. Thus, in an advantageous manner unevenness of the

Be counterbalanced inner wall of the container. It is known that straight extrusion blow molded components have slight wall thickness tolerances, which must be taken into account in the design of built-in parts to be welded to the container wall, at least for those built-in parts which must be tightly welded tightly to the container inner wall, as is the case with a surge tank, for example.

If profile sections are to be provided as the built-in part for the formation of channels or receptacles for lines, it is possible to interpret these built-in parts as a whole of their wall thickness so that wall thickness tolerances of the container inner wall can be compensated during the joining of the built-in parts.

The invention is explained below with reference to an embodiment shown in the drawing.

Show it:

1 shows a section through a fuel tank according to the

Invention, FIG. 2 shows an enlarged sectional view of the detail II in FIG. 1,

Figure 3 shows an alternative embodiment of the mounting flange shown in Figure 2 of the fixed in the fuel tank

Surge tank,

4 shows a further embodiment of the surge tank in the region of its attachment to the inner wall of the container,

Figure 5 shows a fourth variant of the surge tank in the region of his

Fastening with the inner wall of the fuel tank,

FIG. 6 shows a fifth exemplary embodiment according to the invention,

FIG. 7 shows a sixth embodiment according to the invention,

8 shows a partial section through the surge tank of

Fuel tank according to the invention, in which an exaggerated non-planar footprint and mounting surface on the

Inner wall of the container is shown,

Figures 9 and 10, a seventh embodiment according to the invention and

Figures 11 and 12 an eighth embodiment according to the invention.

FIG. 1 shows a simplified sectional view of a fuel tank 1 according to the invention. The fuel tank 1 is designed as an extrusion blow molded plastic hollow body. This was made by extrusion blowing a total of six-layer coextrudate of thermoplastic material with at least one barrier layer for hydrocarbons. Two sheet-like preforms made of thermoplastic material were extruded between the open parts of a three-part blow molding tool. The blow molding tool for producing such a fuel tank 1 comprises at least two outer molds and a central mold, each of the outer molds forming a partial cavity, each defining one half of the hollow body to be manufactured. In a first method step, the respective web-shaped preforms are extruded or arranged between an outer mold and the middle mold. In doing so, the outer forms close against the middle form. In this way, a closed mold cavity is formed, wherein by means of gas pressure of the central mold and / or evacuation of the outer molds, the preforms are each drawn into the partial cavity at the respective outer mold. In the middle mold, component carriers with components arranged on them are preferably provided on a movable frame. About example hydraulically or pneumatically actuated cylinder, the component carrier are arranged movable in the middle mold. By means of this functional components are placed within the container, such that they are used for example in corresponding receptacles on the inner wall of the container.

Alternatively, it is possible to weld in this way functional components made of plastic during the formation of the container with the still plastic inner wall of the container.

Of course, a fuel tank, as will be described in detail below, also be obtained by deep drawing or thermoforming, wherein also in such a method, a welding of functional components can be done with the inner wall of the container.

The container shown in Figure 1 is designed as a fuel tank 1. However, the principle described here is readily transferable to other closed plastic containers with functional components to be provided in them.

The fuel tank 1 is shown greatly simplified. This includes the usual ventilation and exhaust lines and at least one filler neck and pipes for fuel extraction to an internal combustion engine of a motor vehicle. Usually, the fuel from several suction jet pumps various sub-volumes of the fuel tank 1 illustrated here for simplicity only with a single volume in a arranged in the fuel tank 1 surge tank 2 promoted. Within the surge tank 2, which is also referred to as Schlingertopf, at least one electric fuel pump is arranged in a known manner, which promotes from the volume of the surge tank to the engine of the internal combustion engine. Also for reasons of simplification, the fuel pump is not shown here. The surge tank 2 serves to ensure that the fuel pump is supplied with fuel during all driving conditions of the vehicle, that is, during acceleration, deceleration and cornering.

According to the invention it is provided that, for example, the surge tank 2 is connected to the inner wall 3 of the fuel tank 1 such that it defines a separate volume from the filling volume of the fuel tank 1, wherein the inner wall 3 of the container directly serves as a boundary wall of the volume. In other words, the surge tank 2 according to the embodiment described here is formed without bottom. The bottom is formed by the inner wall 3 of the fuel tank 1, wherein the surge tank 2 is provided on its inner wall 3 facing side with a mounting flange 4, which is circumferentially sealed tightly welded to the inner wall 3 of the fuel tank 1. This makes it possible to form the surge tank 2 as a one-piece, injection-molded component, to which all the essential elements are formed. In a conventional manner formed surge tank 2 with a bottom, it is necessary to provide this possibly with a lid closure, which then with the

Baffle 2 is locked. This is necessary to pre-assemble the fuel pump and possibly a level sensor or the like in the surge tank 2, before it is spent in the fuel tank 1.

According to the invention, it is provided that the surge tank 2 during the formation of the fuel tank 1 has been materially connected to the inner wall 3 of the same. In fact, as already mentioned, that the inner wall 3 forms a boundary wall of the surge tank 2. As can be seen from FIGS. 2 to 7, the boundary wall 5 of the surge tank 2 can have an L-shaped or T-shaped profile in the region of the fastening flange 4 with a surface 6 facing the inner wall 3. The joining surface 6 of the mounting flange 4 is formed in the suitably round in cross-section formed surge tank 2 fully encircling, so that this edge sealingly welded to the inner wall 3 of the fuel tank 1 can be welded.

For this purpose, the joining surface 6 is provided with welding ribs or weld extensions 7, the heat capacity is such that they melt in contact with the still hot and plastic inner wall 3 of the fuel tank 1 during its formation and so an intimate cohesive connection of the inner wall 3 on the one hand and joint surface. 6 on the other hand.

In order to compensate wall thickness tolerances of the container wall or even unevenness of the inner wall, the boundary wall 5, as shown in Figures 4 to 8, flexible, such that the mounting flange 4 is flexible or movable within certain limits and, for example, in Figure 8 can take on the right side of the figure shown angled (not rectangular) position with respect to the boundary wall 5 of the surge tank 2. The flexibility of the mounting flange 4 with respect to the boundary wall 5 can be achieved in various ways, for example by providing a circumferential film hinge. Alternatively, the surge tank may have been made of various plastics, for example, over the height of the boundary wall 5 different hard plastics may be provided (for example, hard-soft-hard). In this way, a height compensation of any projections in the inner wall 3 of the fuel tank 1 is possible. Depending on the width and configuration of the mounting flange 4 6 relief slots 8 may be provided in this to avoid undue stresses due to the circular shape of the joint surface.

The invention has been explained above with reference to a surge tank 2. As is also shown in FIG. 1, profile parts 9 can also be provided as built-in parts in the sense of the invention, which have been welded to the inner wall 3 of the fuel tank 1 during the shaping thereof so that they have either closed channels for air and / or fuel or form for receiving cross-sectionally round lines. In the latter case, the profile sections 9a, b engage and hold sections only in these recorded lines.

The profile section 9a shown in FIG. 1 is V-shaped in cross-section, the profile section designated as 9b in FIG. 1 is U-shaped in cross-section. Other geometries are readily conceivable within the scope of the invention. The profile sections 9a, b make use of the concept underlying the invention to use the inner wall 3 of the container as a boundary wall of a volume to be separated from the container. In this way, clamping or locking fasteners for cables can be saved.

As shown in Figs. 9 and 10, the inner wall 3 of the fuel tank may be provided with inwardly projecting ribs 10 or the like which cooperate with corresponding grooves 10a of the surge tank 2 and facilitate its fixed attachment to the inner wall 3 of the fuel tank 1.

Of course, instead of the ribs 10 on the inner wall 3 of the fuel tank 1 there may also be provided grooves which cooperate with corresponding ribs of the surge tank 2.

In the figures 11 and 12, a variant of the surge tank is shown, which consists of a plastic, which does not interfere with the inner wall 3 of the

Fuel tank 1 compatible in terms of weldable. In this case, between the joining surface 6 of the boundary wall 5 and the inner wall 3 of the fuel tank 1, a hot melt adhesive 11 or another suitable Adhesive provided, which produces a material connection in contact with the hot inner wall 3 of the fuel tank 1.

LIST OF REFERENCE NUMBERS

1 fuel tank

2 surge tanks

3 inner wall

4 mounting flange

5 boundary wall

6 joining surface

7 welding processes

8 discharge slots

9a, b profile sections

10 ribs

10a grooves

11 hot glue

Claims

claims

1. container, in particular fuel tank (1) made of thermoplastic material with functional fittings for ventilation, for

Fuel extraction or the like, characterized in that at least one functional component such a material fit with the inner wall (3) of the container is connected, that the functional insert with the container wall defines a volume separated from the filling volume of the container, such that the inner wall (3) of the container directly serves as a boundary wall of this volume.

2. Container according to claim 1, characterized in that as functional components profile sections (9a, b) are provided, which are welded to the inner wall (3) of the container so as to form with these at least partially closed channels or volumes.

3. A container according to claim 2, characterized in that the profile sections (9 a, b) in cross-section semicircular, U-shaped or V-shaped.

4. Container according to one of claims 1 to 3, characterized in that at least one surge tank (2) is provided for a fuel pump which is open on its in installation position of the inner wall (3) of the container facing side and the boundary wall (5) circumferentially cohesively connected to the inner wall (3) of the container.

5. Container according to one of claims 1 to 4, characterized in that the surge tank (2) on its side facing away from the inner wall (3) of the container side is at least partially closed.

6. Container according to claim 4 or 5, characterized in that the boundary wall of the surge tank (2) on the in the installed position of 2

Inner wall (3) of the container facing side has a circumferential mounting flange (4).

7. Container according to claim 6, characterized in that the joining surface (6) of the mounting flange (4) is profiled.

8. A container according to claim 6, characterized in that the joining surface (6) of the mounting flange (4) is provided with melt projections and / or melt approaches.

9. Container according to one of claims 6 to 8, characterized in that the boundary wall (5) of the surge tank (2) at least partially and based on the circumference of the surge tank (2) is at least partially flexible.

10. A container according to claim 9, characterized in that the angle between the mounting flange (4) and the boundary wall (5) is variable.